The present invention relates to piezooptic measuring converters and, more particularly, to sensitive elements of piezooptic measuring converters employed in instruments for measuring force, pressure, acceleration, temperature and other values converted into mechanical stresses of a sensitive element.
There are widely known sensitive elements of piezooptic measuring converters. These sensitive elements have an insert of a piezooptic material, arranged between the foot and the base and rigidly attached thereto.
In such sensitive elements the entire end face surfaces of the feet and bases are in contact with the end face surfaces of the inserts. As a result, changes in the temperature of the inserts, feet and bases lead to mechanical stresses due to a different change in their linear dimensions. Added to the mechanical stress due to a physical value being measured, these stresses produce an error signal.
If the temperature of the above-mentioned parts is uniform throughout the volume of these parts and changes uniformly, the temperature error may be reduced by selecting materials for the feet, bases and inserts having, if possible, an equal temperature expansion coefficient. This is not always possible, however, due to differences in this coefficient within different batches of materials of the same type.
Besides, the method of selecting materials having equal thermal expansion coefficients is altogether ineffective when the temperature of the inserts, feet and bases is not equal and changes in a non-uniform manner, as, for example, in the case of a temperature gradient around a sensitive element or a sharp change in temperature.
It is an object of the present invention to provide a design of a sensitive element of a piezooptic measuring converter which would ensure the rigidity of said sensitive element in the direction of the action of a physical phenomenon being measured (in particular, force).
It is another object of the present invention to provide a sensitive element of a piezooptic measuring converter, which would ensure reliable coupling between the insert and the base and foot.